Justification:
The Kanthan Cave Trapdoor Spider meets the criteria for listing as Critically Endangered because its extent of occurrence (EOO) and area of occupancy (AOO) are well under 4 km² (this is a maximum estimate for EOO and AOO based on the recommended grid size of 2x2 km), it is known from a single location and there is a potential threat of quarrying, which when it happens, will result in a continuing decline in extent of occurrence, area of occupancy, extent and quality of habitat, number of subpopulations and number of mature individuals. The estimates of actual EOO and AOO are much smaller, being 0.014 km² and 0.003 km² respectively.

This species is known from a single cave situated in a limestone hill named Gunung Kanthan, at 4°45.685'N, 101°07.322'E, Perak State, Malaysia. A survey in 2001 showed that the cave was 435 m long (see Figure 1 in the attached PDF). The cave is up to about 40 m high. A large entrance, rather high up the hill, slopes down into a more constricted passage leading into a large chamber with an opening overhead. The chamber gradually becomes smaller and leads to an exit. A meandering stream has cut into the cave floor, but the water appears to be stagnant. In this cave, all the specimens are found in nests on the cave walls (Platnick et al. 1997; Price 1998, 2011, Murphy and Murphy 2000) but only in one part of the main chamber (L. Price pers. comm.). The cave lies between 125 and 135 m above sea level.On the closest limestone hill, Gunung Tempurung, another species of Liphistius is found (Platnick et al. 1997).

Liphistius kanthan builds its nest on the cave wall or floor and camouflages it with mud and dirt. The front door of the nest is a trapdoor with 6-8 signal threads or trip wires radiating out. The spider waits with one leg on each thread, and if prey trips the wire, the spider rushes out, catches the victim and runs home slamming the door. If, however, the prey turns out to be an enemy, the spider can escape by means of a back door. After mating the female hangs an egg sac below her nest. The juveniles leave this sac and make their own nests (Platnick et al. 1997, Price 2011).

The major threat is the limestone quarrying of the site by Lafarge Malaya planned for 2013 (Price 2012) which has already eliminated the northern two-thirds of what was once a two-peaked hill. The southern part of the hill is the part with the cave and it is within their permitted concession. Press reports in 2013 indicated that Lafarge Malaya would start quarrying the hill in June 2013 but the company headquarters said that it is unlikely to start for up to 18 months (i.e. early 2015.). Given that the extent of small fissures is unknown, not only is the actual extent of this spider within the cave system unknown but also the risks of the humidity, air flow and light within the cave cannot be estimated and so the impacts of even a single blasting of the external rock cannot be assessed – but is likely to be disastrous.

There are no conservation actions in place. The most effective feasible action is the protection of this last, unquarried section of Gunung Kanthan and/or the legal protection of the species. Approaches to protect the site have been made recently to the Malaysian National Heritage Office in part because of the presence of temples at the mouth of the cave, but also because of the presence of this spider.